Multipunch system for flexible film products



United States Patent Inventors Richard C. Adams West Barrington, R.l.; William S. Coombes, Somerset, Mass. Appl. No. 823.853 Filed May 12,1969 Patented Dec. 29, I970 Assignee G. T. Schjeldahl Company Northlleld. Minn. a corporation of Minnesota MULTIPUNCII SYSTEM FOR FLEXIBLE FILM PRODUCTS 10 Claims, 9 Drawing Figs.

US. Cl 83/99. 83/l23. 83/3 l5. 83/527. 83/528, 83/573, 83/69l 83/695 Int. Cl B26f 1/04, B26f l/06 Field olSeareh 83/98, 99, l23. 318. 528. 571. 572, 573. 69L 527. 695

References Cited UNITED STATES PATENTS 2,204,405 6/ I940 Dunlap 83/528 Primary Examiner-James M. Meister Attorney-Orrin M. l-laugen ABSTRACT: Punching means for perforating thin flexible webs of material comprising frame means supporting a carrier plate in superimposed relationship over the material to be perforated, a plurality of punch members retained within bores formed in the carrier plate, each punch member being mounted for free axial rotation within. these bores, the punch including a cutter head with means resiliently biasing the punch member toward the top of the carrier plate and against an abutment bar or means, the punch members further including a shank portion having a top abutment surface with axial and radial segments removed therefrom to form additional abutment surfaces axially spaced from the upper surface of the shank. The arrangement is such that upon rotation of the shank, the cutting surface or cutting edge of the punch may be arranged in predetermined axial disposition relative to the material being perforated, thus permitting a variety of operations including punching, perforating, or the like with a single punch device. Preferably, the cutting surface of the punch is serrated so as to provide a basis for forming bores, or perforations, depending upon the axial disposition of the punch.

PATENTED 058281976 SHEET 2 OF 3 VEN'IURS /C//,4ED 6. 404/145,

MULTIFUNCII SYSTEM FOR FLEXIBLE FILM PRODUCTS The present invention relates generally to means for perforating thin flexible webs, and more particularly to apparatus for cutting or perforating thin plastic sheets. The device includes a carrier plate which is adapted to be moved reciprocatorily up and down, the carrier plate being provided with a number of spaced bores to receive punch members therewithin. The punch members are further adapted to be' disposed in a variety of axial dispositions relative to the carrier plate, so that in one extreme axial disposition, a through-cut or bore may be formed in the plastic sheet; in an intermediate disposition, a serrating cut may be made; and in the other extreme axial disposition, no operation is conducted on the film whatsoever. Thus, the operator may preselect the punch desired, and may also preselect the operation to be performed by the punch.

It is frequently desirable to have openings formed in the walls or sides of certain devices fabricated from plastic sheets, such as plastic bags or the like. In one common application, plastic bags are perforated so as to provide ventilation for a product retained therein. Since most plastic bags are constructed from rolled sheet material which is formed and cut consecutively as the material is unrolled, it is convenient to punch or cut holes in the film or sheet material just prior to the finishing of the plastic bag. The present apparatus provides a versatile apparatus which may be quickly set up and which has a wide variety of cutting or perforating capability so as to permit the preparation of an equally wide variety of finished products, particularly those products prepared from plastic sheets using rolled material.

While a wide variety of equipment may be utilized for forming holes in thin plastic sheets, the changeover operation limits the application of most equipment to specific operations only. The apparatus of the present invention provides a device which is highly versatile in performing a wide variety of cutting or perforating operations.

Generally, the apparatus of the present invention includes a frame means which is adapted to support a carrier plate in superimposed relationship over a web of plastic sheet material forming the work, the carrier plate having a plurality of spaced bores formed therein to receive a plurality of punch members. Each punch member is mounted for axial rotation within the bore and includes a cutter head with means resiliently biasing the punch member toward the top of the carrier plate and against a certain abutment means. The punch member further comprises a shank portion which is provided with a top abutment surface, and additional abutment surfaces which are formed due to the removal of certain axial and radial segments from the shank portion. The immediate radial disposition of the shank portion will determine the abutment surface contacting the abutment means on the carrier plate, and thus the axial disposition of the cutter head. The cutter head is preferably provided with a serrated surface, so as to enable the cutter to provide a completed bore or hole in the plastic sheet, a serrating cut, or no cut at all, depending upon the axial disposition.

Therefore, it is an object of the present invention to provide an improved punching means for thin flexible webs, the punching means including a carrier plate for supporting individual punches in axial spaced relationship, means being provided to control the axial disposition of the punch so as to modify and control the operation performed on the work during reciprocation of the the carrier plate.

It is yet a further object of the present invention to provide a carrier plate for supporting a multitude of individual punches for punching holes in thin flexible webs, the axial disposition of the individual punches being controllable so as to modify the immediate operation of the punch upon the work.

It is yet a further object of the present invention to provide a versatile punching apparatus for forming holes in thin flexible webs, the punching means having a wide variety of capability for forming holes, or serrations in the plastic material, depending upon the axial retention of the punch, the individual punches being provided with means for readily rotating the shank so as to change or alter the position and operation of the cutter head of the individual punch member.

Other and further objects of the present invention will become apparent to those skilled in the art upon a study of the following specification, appended claims, and accompanying drawings wherein:

FIG. 1 is a perspective view ofa segment ofa flexible plastic sheet film converting apparatus. of the type typically used for the fabrication of plastic bags and the like, and illustrating the manner in which the apparatus of the present invention is mounted and received on the converting apparatus;

FIG. 2 is a detail elevational view, partially in section, of one end of the improved punching means;

FIG. 3 is a detail end view of the carrier plate supporting the individual punches, and taken along the line and in the direction of the arrows 3-3 of FIG. 2;

FIG. 4 is a detail perspective view of a segment of the carrier plate supporting the individual punches, and showing the individual punches in varying axial dispositions;

FIG. 5 is a perspective view of one means of driving a pair of punch carrier plates in reciprocatory up-and-down motion and along a predetermined path;

FIG. 6 is an elevational view of one typical cutter head which may be employed in connection with the apparatus of the present invention;

FIG. 7 being the result of such an operation when the cutter head penetrates the film to the depth shown in FIG. 6', and

FIG. 8 is a view similar to FIG. 6 of an alternate cutter head which may be employed in connection with the apparatus of the present invention, with FIG. 9 illustrating the result of a cut formed in a plastic film when the cutter head penetrates to the extent shown in FIG. 8.

In accordance with the preferred modification of the present invention, and with particular reference to FIGS. 1--5 of the drawings, the converting assembly generally designated 10 as shown in FIG. 1 includes a frame means 11 supporting a web of flexible sheet material 12 which extends from the supply roll 13 across a suitable idler means such as at [4. The cutter assembly generally designated 15 is employed in superimposed relationship over the moving web 12 and is provided with a carrier plate 16 which carries a plurality of in dividual punches therewithin. Means are provided for reciprocably moving the carrier means 16 so as to move the punches in an axial direction through the surface of the web 12.

With particular attention being directed to FIG. 2 of the drawings, the carrier plate 16 is supported by and between a pair of lateral plates such as the plate 17, the corresponding lateral plate on the opposite end of the carrier plate 16 not being shown. A projecting drive pin I8 is shown, this pin being secured to plate 17 so as to accommodate and provide reciprocatory motion for the plates 16 and I7. A rotatable cam follower surface 20 is provided to function cooperatively with cam bar 21, cam bar 21 being secured by means of suitable pins such as the pin 22 to the crank arm 23. Crank arm 23 is secured at its upper end by locking collar 24 to the axially rotatable drive shaft 25. As is illustrated in FIG. 5, and as will be referred to in greater detail hereinafter, drive shaft 25 is driven by suitable reciprocating drive mechanism, it being understood that the reciprocatory up-and-down motion of the carrier plate I6 is achieved by virtue of the pivotal reciprocatory rocking motion of drive shaft 25. In order to assist and accommodate the carrier plate 16 in its reciprocatory motion, stationary guide pins are provided as shown at 2646, these pins being preferably resiliently biased by means of the compressible spring member 27.

Turning now to the details of the individual punches which are held and retained by the carrier plate 16, it will be observed that a plurality of bores are formed in the plate 16 such as at 30, for example. These bores are formed in regularly spaced relationship, such as on l-inch or lie-inch centers.

Disposed within each of these bores is'a punch member such as the punch member generally designated 31. This punch member includes a cutter means as at 32, the cutter means being secured to the shank portion 33 by means of a suitable coupling thread or the like as is shown at 34. The core of the cutter head is provided with a bore for a purpose to be hereinafter explained in detail. A compression spring 36 resting upon a suitable base plate 37 is provided to resiliently urge the punch member 31 in a direction toward the top of the carrier plate. This force accordingly causes contact between the punch member 31 and the abutment means or plate 40, abutment plate 40 being secured or attached to the top surface of carrier plate 16 by means of suitable screws 41, for example. A study of the axial dispositions of theindividual punch members shown in FIG. 2 indicates that they are at variance, one from another.

Turning now to FIG. 4, and with continued reference being directed to FIG. 2, it will be seen that an axial and radial segment has been removed from the head portion 45 of the shank 33 of punch member 31. This provides a second abutment surface as at 46, this abutment surface being arranged to be in contact with abutment plate 40 when the head 45 is rotated counterclockwise, in the direction of arrow 47, for an arcuate distance of 90. The spring 36 will accordingly force the head member 45 to a position such as is shown in the punch member disposed at the second position from the left in FIG. 4.

If desired, it is possible to provide an additional abutment surface at a different axial disposition, and for a description of this feature, attention is directed to the punch generally designated 50. This punch includes a head 51 which has been cut away both axially and radially to provide an additional abutment surface 52, this being in addition to the abutment surface shown at 53. Abutment surface 53 corresponds to abutment surface 46 described hereinabove. The purpose of the additional abutment surface is to permit the formation of butterfly vents, or the like, such as is shown at 55 is the web 12.

In order to assist in the punching operation, a base pad is shown as at 60, this base pad being provided with spaced bores such as at 61 and 62 for cooperating with the punch members as they pass through the surface of the web of film 12. This is shown in FIG. 2, for example.

As previously indicated, the vertical reciprocatory motion of the carrier plate 16 is guided by the pin 26. This pin is secured to the carrier plate 16 by any suitable locking means, such as the split locking pin 65. The pin 26 is, as indicated, slidably received within the bore 66 formed in the guide plate 67. Guide plate 67 is locked to the flange area 68 of the lateral support frame 69. The locking action is achieved by virtue of the threaded locking member 70, which, for convenience, is provided with a knurled edge surface as at 71. It will be appreciated that fine adjustments of the longitudinal disposition of the punching means may be accomplished in this fashion.

With particular reference now being made to FIGS. 2, 3 and 5, a description of the means for achieving reciprocatory upand-down motion will now be explained. While various means may be utilized to accomplish this purpose, such as, for example, by utilizing a main drive mechanism, separate drives are, of course, acceptable. The source of energy in the example here is the motor 75 having an output shaft 76, cam 77 being secured to the shaft 76. The cam 77 operates in contact with cam follower 78, which is appropriately secured or fastened to bellcrank 79. Bellcrank 79 pivots about mounting shaft 80, and is resiliently biased by means of the resilient spring member 81, as indicated. At the free end of the crank 79, a suitable pin and bushing are utilized as at 83 to couple the actuating arm 84 to the crank 79, for achieving intermittent rocking motion of the drive shaft 25. This motion is achieved by virtue of the coupling of the crank 86 to rod 84 by means of suitable couplings as at 88.

As previously indicated, the reciprocatory pivotal or rocking motion of shaft moves the crank 23 in an arcuate path, this motion carrying cam bar 21 in a reciprocatory upand-down direction. This motion is delivered to carrier plate 16 through the cam follower 20. It is generally preferred that cam bar 21 be provided with a second idler crank. such as at 89, so as to form a parallelogram.

If desired, more than one carrier plate may be provided, such as is illustrated in FIG. 5, the system there shown including carrier plates 16 and 16A. In this fashion, it is possible to obtain both transverse and axial spacing for the individual bores to be formed in the web as it moves beneath the punching mechanism. For production purposes, it may in certain instances be desirable to equip the apparatus with three or more such units.

Turning now to FIGS. 6, 7, 8 and 9, these FIGS. illustrate certain of the punching or cutter heads which may be employed in connection with the apparatus of the present invention. As is illustrated in FIG. 2, the individual punches are mounted upon the shank portions of the punch members by threaded engagement or the like. Various diameters of punches may be employed, without significant restriction, and the design of the cutter heads is preferably of the serrated style. In addition, it may be desirable to' form a cutter head with serrations, with a pair of axial slots being formed at the root of oppositely disposed serrations so as to permit the formation of a butterfly vent of the type shown in FIG. 9, with the punch being illustrated in FIG. 8. Thus, it will be appreciated that a variety of punches may be employed in connection with this apparatus in order to achieve a variety of results.

With continuing reference being made to FIG. 2, a means is illustrated for removing slugs created upon operation of the punch. This means includes a manifold area or zone 90 (shown capped with cover plate 90A in FIG. 3) formed within carrier plate 16, means being provided as at 91 for coupling the manifold to a suitable source of compressed air or the like. In this connection, manifold 90, which extends continuously along the axis of carrier plate 16, is arranged at a predetermined level thereacross. The individual punch members are provided with circumferential slots at an axial disposition coinciding with the placement of the manifold 90 whenever the punch members are inserted into the carrier plate 16 at a flow cutting" depth. Radial channels such as is shown at 92 are provided to provide communication with the axial bore 94 formed in the shank portion of the punch member. This bore 94 provides a continuation for the axial bore present in the individual punch members, such as the bore 95 shown in the cutter 32A. In actual operation, compressed air will preferably be provided on an intermittent basis to manifold 90, thus providing intermittent pulses for removal of slugs from the ends of the individual punch members. In order to avoid unwanted pulses of compressed air at this location, the system is operational only when the punches are in a flow cutting" disposition.

While the system illustrated herein is adapted to function while the film or web 12 is at dwell, it is, of course, obvious that the system could be used on a continuously moving web as well. Such an arrangement would, of course, necessitate a modification of the drive means, however it is pointed out that such operation is contemplated and certainly well within the capability of this device.

In order to prepare the system for use, the operator will mount the device on the frame provided for the converting assembly, such as is illustrated in FIG. 1. Thereafter, the system is checked in order to provide proper synchronism with the main converter assembly and once synchronized, the system may be placed in continuous operation. While the fine adjustments have been shown and discussed hereinabove, it will be, of course, appreciated that the operator will perform a course adjustment when the lateral members 69 are secured to the frame member 11. Furthermore, if desired, a bag may be mounted on the underside of the assembly in order to capture slugs which are removed from the web 12 during operation.

We claim:

1. In combination with means for supporting and moving a web of flexible sheet material along a certain predetermined path; punching means for perforating said webs comprising:

a. frame means supporting a carrier plate in superimposed relationship over said predetermined path;

b. a plurality of punch members retained within bores formed within said carrier plate, each punch member being mounted for axial rotation within said bore and including a cutter head with a shank portion secured thereto;

c. means resiliently biasing each of said punch members toward the top surface of said carrier plate and against an abutment means, said abutment means being disposed over a portion of said bore; and

d. each of said cutter heads having a cutting surface at the tip end thereof, each of said shank portions having a top abutment surface with an axial and radial segment removed therefrom to form a second radial abutment surface axially spaced from said top abutment surface whereby upon rotation of said shank portion, said cutting surface may be arranged in a plurality of stable axial dispositions.

2. The punching means as defined in claim 1 being particularly characterized in that the shank portion of said punch members is of cylindrical form.

3. The punching means as defined in claim 1 being particularly characterized in that said cutting surface is a serrated cutting surface.

4. The punching means as defined in claim 3 being particularly characterized in that said serrated cutting surface is provided with axially extending slots.

5. The punching means as defined in claim I being particularly characterized in that said shank portion has second axial and radial segments removed therefrom to form a third radial abutment surface at an axial disposition spaced from said second radial abutment surface.

6. The punching means as defined in claim 5 being particularly characterized in that said cutting surface is a serrated cutting surface with at least one axial slot extending from the rootjuncture of adjacent serrations.

77 The punching means as defined in claim 1 being particularly characterized in that the shank portion of each punch member is provided with means for removably securing a cutter head thereto.

8. The punching means as defined in claim 1 being particularly characterized in that the bores formed within said carrier plate are arranged at regular intervals thereacross.

9. The punching means as defined in claim 1 being particu larly characterized in that said cutter head has an axial bore formed therein, and wherein means are provided for removal of slugs from said flexible web.

10. The punching means as defined in claim 9 being panicularly characterized in that said means for removal of slugs includes a manifold within said carrier plate having means coupling the manifold to a source of compressed air, the shank portion and cutter head portion of each punch member having an axial bore communicating with the cutting surface and a radial bore communicating with said axial bore when said shank is mounted within said carrier plate to hold said cutting surface in web perforating disposition. 

